Stainless steel is a highly versatile material that is widely used in a variety of industries. Whether you need to manufacture parts with excellent corrosion resistance or high tensile strength, you can find a stainless steel grade that meets your requirements. Among the many alternatives, two grades, in particular, are often pitted against each other: stainless steel 17-4 PH vs 316. In this blog post, we will explain the key differences between these two grades and help you decide which one is best for your application.
Difference Between Stainless Steel 17-4 PH and 316
Chemical Composition
Stainless steel 17-4 PH and 316 have different chemical compositions. 17-4 PH contains 15-17% chromium, 3-5% nickel, 3-5% copper, 3-5% manganese, and 4-5% molybdenum. Meanwhile, 316 contains 16-18% chromium, 10-14% nickel, and 2-3% molybdenum. Adding copper and manganese in 17-4 PH improves its mechanical properties, while the higher nickel content in 316 enhances its resistance to corrosion.
Corrosion Resistance
Corrosion resistance is one of the most critical factors when choosing a stainless steel grade. 316 is known for its excellent resistance to general corrosion, high-temperature oxidation and pitting corrosion. On the other hand, 17-4 PH can handle high-stress corrosion cracking better than 316, thanks to its higher copper content. However, 17-4 PH’s resistance to general corrosion is inferior to 316’s.
Mechanical Properties
Regarding mechanical properties, 17-4 PH and 316 differ significantly. After heat treatment, 17-4 PH is a precipitation-hardening grade that exhibits high tensile strength and hardness. Its yield strength can reach up to 1100 MPa, making it suitable for applications that require excellent mechanical properties. 316, on the other hand, is known for its excellent ductility, toughness, and formability. However, its mechanical properties are lower than 17-4 PH.
Application
Choosing the right stainless steel grade for your application requires considering several factors. In general, 316 is more suitable for applications that require high resistance to general and pitting corrosion, such as the marine and chemical industries. Meanwhile, 17-4 PH is ideal for applications that require high strength and resistance to high-stress corrosion cracking, such as aerospace and defence.
Conclusion:
Stainless steel 17-4 PH and 316 are excellent materials but serve different purposes. 17-4 PH offers exceptional mechanical properties, while 316 has superior corrosion resistance. When choosing the right grade, it is crucial to consider your application’s needs and requirements. If you need help selecting the right stainless steel grade for your application, consult a reputable supplier who can guide you.
